[ 3 2 4 ] 
‘Cufnion or the hand, was firil improved by the addition of a leathern flap; then by 
•moiftenirig the rubber; afterwards by applying the amalgam; and, laftly, by the 
addition of a fiik hap, p. 278. Experiments on the luminous appearance of eleblri- 
city and the abtion of points, ibid. The efcapc of negative elebtricity from a bail 
attended with the appearance of ftrait fharp fparks with a hoarfe or chirping noife, 
pp. 278, 279. A variety of bails in electricity unneceflary, p. 280. Volta’s 
opinion, that a point is the coating to an infinitely fmall plate of air, erroneous, p. 
281. In any elebtrifled conductor the tranfltion or efcape of electricity will be made 
chiefly from that part of the furface which is the moil remote from the natural flate, 
p. 282. Thicker glaffes require much lefs electricity to produce an intenfity which 
breaks them than thinner do, p. 284. The perforation of glafs by the long fpark, or 
by the fpark through oil or cement, fuppofed to depend on the intenfity of theele&ri- 
city, which has not time to diffufe itfelf, but charges a minute part of the furface 
very high, p. 285. Mufcovy talc, a very perfect non-condubtor ; capable of being 
divided into plates of lefs thicknefs than a two-hundredth part of an inch ; in confe- 
quence of its great capacity gives very ftrong elebtric fhocks ; and its laminae, con- 
trary to the aflertion of Beccaria, are naturally in ftrong oppofite ftates of elebtricity, 
and flafh to each other when torn afunder in the dark, ibid. 
Euler’s hypothefis of refrabtion of the differently refrangible rays of light proved to be 
falfe, p. 257. His hypothetical principle neither fit for rendering a telelcope achro- 
matic, nor to account for the diftinbtnefs of the human viflon, ibid. \ 
Excitation of electricity, experiments on, p. 265. Strength of the excitation afeer- 
tained, ibid. Silk the chief agent in excitation of elebtricity, p. 271. 
Experiments and obfervations on the principle of acidity, the compofition of water, and 
phlogiflon, p. 7. Experiments on the phlogiflication of fpirit of nitre, p. 139. 
Experiment proving that beat and not light gives colour to fpirit of nitre, p. 140. 
Experiments on the congelation of quickfilver in England, p. 199. Experiments 
relating to the produbtion of artificial cold, ibid. Experiment proving that mercury 
may be frozen not only in England in fummer, but even in the hotteft climate, at any 
feafon of the year, p. 202. Experiments illuflrating the fubjebt of producing cold, 
pp. 209, 210. Experiment illuftrating the theory of viflon, p. 261. Experiments 
and obfervations on elebtricity, p. 263. Experiments fhewing that the office of filk 
is not merely to prevent the return of elebtricity from the cylinder to the cufhion, 
but that it is the chief agent in the excitation ; while the cufhion ferves only tofupply 
the electricity, and perhaps increafe the prefiure at the entering part, pp. 263, 266. 
Experiments on the luminous appearances of elebtricity and the abtion of points, p. 
278. Experiments on the abtion of points in elebtricity, pp. 281, 282. Experi- 
ments on the tranfmiflion of the vapour of acids through an hot earthen tube, and 
further obfervations relating to phlogiflon, p. 289. Experiment on oil of vitriol, 
ibid. Experiment on fpirit of nitre, p.291. Experiment in which alkaline air is 
converted into inflammable air, p. 295. Experiments relating to the dobtrine of 
phlogifton 3 
